The embodiments described herein relate generally to the trucks of a skateboard. More particularly, the embodiments described herein relate to a skateboard truck configured to lower the center of gravity and improve the ride quality of a skateboard.
Skateboards are a known means of activity and transportation. Standard skateboards generally include a deck, a pair of trucks, and a set of bearings and wheels. Various skateboard designs exist and are generally configured to tailor to a particular riding style or function. For example, a longboard is used as a means of transportation or “cruising” due to the fluidity of motion.
Often, the deck of a longboard ranges in length between 33 in. to 59 in. and can define various shapes and configurations. For example, a pintail design includes a deck with a teardrop shape configured to allow room for the wheels to spin freely without contacting the bottom surface of the deck. As such, the trucks can be mounted to the bottom surface of the deck and thus, the pintail design defines a relatively high center of gravity. In some instances, the relatively high center of gravity can lead to instability.
In other instances, the longboard can include a drop through truck design. With this design, the center of gravity is lower than the design in which the trucks are mounted to the bottom surface of the deck. The drop through design is configured such that the mounting plate of the trucks is secured to the top surface of the deck and the other components of the trucks (e.g., the pivot cup, kingpin, hanger, bushings, etc.) extend through a cutout portion of the deck. While the lowered center of gravity provides the rider with more stability, the cutouts in the deck result in relatively large stress concentration risers. The presence of stress concentration risers can lead to cracks or splits in the deck propagating from the stress concentration risers. In some instances, the cracks or splits can lead to a catastrophic failure of the deck (e.g., the deck breaks into multiple pieces) under a load (e.g., the force applied by the weight of the rider). Additionally, the securing of the mounting plates of the trucks to the top surface of the deck results in the bolts being in tension when under the load of the rider. The constant tensile force can cause the nuts to work loose from the bolt, resulting in the mounting of the trucks to the deck to loosen.
FIGS. 1 and 2 illustrate a skateboard in a known configuration. In such a known configuration, a skateboard 100 includes a deck 110, a pair of trucks 130, and a set of wheels 150. The skateboard 100 can be, for example, a longboard skateboard with a “drop through” truck configuration. In such configurations, the trucks 130 include a base plate and a hanger. The hanger is coupled to the base plate in a known configuration. The base plate mounts to a top surface 117 of the deck 110 at a mounting location 113. In this manner, the hanger extends through an opening 115 from the top surface 117 through to the bottom surface 118. In such a configuration, the distance from the base plate to the center of the axle is approximately 62.4 mm.
The openings 115 are a given shape such that the base plate mounts to the top surface 117 of the deck 110 and the hanger 130 extends through the opening 115. As shown in FIG. 2, the opening 115 defined by the deck 110 is a large opening configured to receive the entirety of hanger of the truck 130 therethrough. In such known configurations, the opening 115 defines a discontinuity in the deck 110 and thus defines stress concentration risers inherent in a discontinuity. As used herein, a stress concentration riser is any given geometry, discontinuity, cutout, and/or the like, that increases the stress of a given material at a given location. The opening 115 includes relatively large stress concentration risers due to the size and/or geometry of the opening 115 through which the trucks 130 are mounted. Such stress concentration risers can lead to cracks propagating from the location of the stress concentration riser, such as, the small radius corners of the opening 115, and can result in the deck cracking and/or breaking to the point of being unusable.
Thus, a need exists for improved methods and devices for lowering the center of gravity and improving ride quality of a skateboard, while maintaining the structural integrity of the deck.